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Sleeping pads for cold weather


kweb

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I have noticed that many gear lists for Denali suggest using 2 pads... a therm-a-rest and the ridge rest. Combined they offer an R value of 5.2. and weight of 30ozs (3/4 length ultra light and full length ridge rest). I currently use a Mt. Hardware High Mt. 60. R value is 6.75 and weighs 32ozs. While the overall thickness of the combo is 1.63" (compaired to 1.125"), 4 ounces lighter and 12" longer....The Mt. Hardware pad has a higher R value. What do you all think is a better choice? grin.gif" border="0

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kweb,

I took two pads my first time up there. It was a bit better with two, but one is fine. I have used one pad for years. I use a thick ridgerest, which I cut down in length to my exact height so it isn't too bulky. I personally don't like Thermarest's because they eventually find a way to get a hole in them, and they are too heavy.

If you plan on having a fat basecamp somewhere to use between climbs, then bring two, but for alpine climbs one is all I recommend. The snow isn't any colder on Denali than anywhere else.

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Seems I once read that closed-cell foam is always warmer since what really counts is "dead air", not thickness. Open-cell inflatables (like the Therma-Rest) supposedly allow for little internal air currents which conduct heat away from you. It's kind of like a double-pane storm window. One might think that a bigger gap between panes would provide more insulation, but in reality, the warmth of the inner pane causes adjacent air (or some kind of gas) between the panes to rise, while the cool outer pane cools the adjacent air, causing it to fall. When the gap between panes is thick enough, a current sets up in which air on the warm side of the gap rises to the top and then shifts to the cold side and falls into the cold side of the gap (replacing the cold air that falls down). The falling cold-side air eventually shifts to the warm side to replace the rising warm air. Of course, this circulation takes warmth away from the inner pane and transfers it to the exterior of the home. Storm windows are actually designed with a very narrow gap between panes to discourage these little "heat-pump" currents.

The combo-system is supposed to be more comfortable. Some people find that a closed-cell pad on top of packed snow is just too hard for their liking.

Two pads in the winter is a rule for me. If you find that sleeping on your side keeps you warmer than sleeping on your back, that's a sign that you could benefit from a second pad.

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Actually, the snow is colder anywhere the temperature is colder. Snow will not be 32 F if the temperature is -70 F. If it drops below what your padding will insulate you from, you will get cold from below.... Denali can be frigin bug freezing cold too. Still, it is a good idea to pack as light as possible without shorting yourself on the essentials. Lizard brain probably has it right. I do the same basic thing. I also take a thermarest for base camp but mostly because I have an old shoulder injury that acts up if I sleep on it on hard ground.

Lots of people go up there in May-June and never see the really cold weather that can and does happen accaisionally. Don't underestimate what Denali can throw at you. There are a few frozen people up there who guessed wrong. frown.gif" border="0

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quote:

Originally posted by Bug:
Actually, the snow is colder anywhere the temperature is colder. Snow will not be 32 F if the temperature is -70 F. If it drops below what your padding will insulate you from, you will get cold from below.... Denali can be frigin bug freezing cold too. Still, it is a good idea to pack as light as possible without shorting yourself on the essentials. Lizard brain probably has it right. I do the same basic thing. I also take a thermarest for base camp but mostly because I have an old shoulder injury that acts up if I sleep on it on hard ground.Lots of people go up there in May-June and never see the really cold weather that can and does happen accaisionally. Don't underestimate what Denali can throw at you. There are a few frozen people up there who guessed wrong.
frown.gif" border="0

Okay I guess my science facts are a little off. You're probably right. My first trip up there was in early April on the Muldrow- we got trapped on the Harper in a three day storm, during which time the mercury read -60 at night/-40 during the day for three days, a bunch of our shit blew away, including me flying ten feet airborne in a gust (i'm not exaggerating) that had to have been 125 mph+ while I was outside trying to resecure our tent guylines. I lost 17 pounds in 20 days while on a 6000 calorie a day diet. My facts on the snow temperature are off because I think my brain got frostbite on that trip. which explains everything else about me. rolleyes.gif" border="0

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quote:

Originally posted by moron:
Yeah, yeah, a foam and thermarest is great, but resolve this one - which one goes on the bottom?
[Wazzup]

I would suggest that you alternate between the two choices. This way, they're more likely to perpetuate that spark between them.

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quote:

Originally posted by NoBolt:
Pads are for Wimps! I sleep on my gear.

I'm sure that would be incredibly comfortable for three weeks. Not to mention if you got stuck in your tent during a storm and were lying on all your stuff for a week straight.

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"My first trip up there was in early April on the Muldrow- we got trapped on the Harper in a three day storm, during which time the mercury read -60 at night/-40 during the day for three days, a bunch of our shit blew away, including me flying ten feet airborne in a gust (i'm not exaggerating) that had to have been 125 mph+ while I was outside trying to resecure our tent guylines. I lost 17 pounds in 20 days while on a 6000 calorie a day diet. My facts on the snow temperature are off because I think my brain got frostbite on that trip. which explains everything else about me."

Dude! Great story. Hope you 're not typing with one finger. If that's not funny, slap me. Er... poke me.

Closed cell definately belongs closest to your body if it gets cold enough to wonder about it. [geek][sleep]

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Last time I was on Rainier, I only had 3/4 length Z rest and a 45 degree bag. I was uncomfortably cool at night. By the end of night one, tent in the same location, I was laying in a bowl. You know, when your body had melted the snow under where your torso has been. shoulder blades and ass stayed cold.

Why do sleeping bag manufacturers even bother to put highly compressable insulation on the bottom of bags. You just crush it flat when laying on it.

It stands to reason that to get the same temp rating out of a bag, remove the insulation from the bottom of the bag and distribute it on top.

Or to have the same weight sleeping system, remove the insulation from the bottom and have a better pad.

Kweb, remember that sleeping bag ratings are based on 2 1/2" of padding.

tongue.gif" border="0

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quote:

Originally posted by kweb:
I have noticed that many gear lists for Denali suggest using 2 pads... a therm-a-rest and the ridge rest. Combined they offer an R value of 5.2. and weight of 30ozs (3/4 length ultra light and full length ridge rest). I currently use a Mt. Hardware High Mt. 60. R value is 6.75 and weighs 32ozs. While the overall thickness of the combo is 1.63" (compaired to 1.125"), 4 ounces lighter and 12" longer....The Mt. Hardware pad has a higher R value. What do you all think is a better choice?
grin.gif" border="0

Take them both.

I don't understand the discussion here--you are asking about Denali right? Its not like you're doing it Twight style in a single 4-hour push from Kahiltna International Airport. You're pulling a fucking sled, fer crissakes. Take all the damn pads you can carry, along with a few camp chairs and a gas-fired BBQ. You'll be damn glad you did. When your tent-bound for a week at 14K trying to negotiate the indentations in the snow melted out from the lack of protection your puny .3mm thick, 6" long frame pad that you pulled from inside your pack. . jesus, someone stop me now.

You're going to have plenty of time to think about what you left behind. Bring an extra pad. You'll be glad you did. Put all the light stuff in your pack, load the sled with the heavy stuff then tell your partner you have lower back problems and can't pull a sled.

Have a good time and sleep well.

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quote:

Originally posted by Bug:
Dude! Great story. Hope you 're not typing with one finger. If that's not funny, slap me. Er... poke me.

Got all ten fingers and toes. I got some very minor frostnip on my fingertips but amazingly that was all. Can't say the same for one of my partners, who lost the ends of two toes, and also got frostbite on two fingers each hand. We had to move during the storm, in 50 mph winds and forty below(an improvement from earlier...), to get into a more sheltered place. Not good, especially when you haven't been able to operate the stove the past 36 hours and are dehydrated as a result.

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